44 FIELD AND WOODLAND PLANTS 



microscope, will show the nature of the branch it was destined to 

 produce ; and, in the case of buds which represent, in embryo, 

 branches bearing flowers, or both leaves and flowers, it is often 

 an easy matter to see the whorls of the future flowers, and even 

 the pollen cells in the anthers and the ovules in the ovary. 



Interesting as it is to study the structure of buds in their dormant 

 condition during winter and early spring, even more fascinating is 

 the watching of the gradual expansion of the bud and the unfolding 

 of the young leaves. And it is not always necessary to make frequent 

 visits to the woods in order to carry out such observations, for a 

 large number of buds will develop almost equally well, at any rate 

 through their earlier stages, if the twigs bearing them be placed in 

 vessels of water either in or out of doors ; and in many cases all the 

 stages from dormant bud to perfect leaves and fully-expanded flowers 

 may be watched in this way. 



We have spoken of the protection afforded to the dormant 

 bud during the winter period, but it is interesting to note that 

 protection is necessary for the young leaves even after they have 

 forced themselves well out into the light and air. The reason for 

 this is that the epidermis or outer skin of the young leaf is not 

 properly developed. It is not yet water-tight, and, consequently, 

 the sap of the tender leaves would rapidly evaporate, so that they 

 would soon become dry and shrivelled. 



The means by which the young leaves are protected will be 

 readily seen if we watch the gradual development of the bud. In 

 many cases these leaves remain folded long after they have left 

 the shelter of the original bud-scales, the manner of folding being 

 the same as that which obtained while within the bud. Sometimes 

 they are folded like a fan, or like the leaves of a book ; sometimes 

 rolled one within the other, or irregularly crumpled in such a 

 manner that nothing is exposed to the air except the edges of the 

 leaves and the surfaces of the veins. 



In addition to the protection from evaporation afforded by the 

 folding of the young leaves, many are covered with a dense coat of 

 ' ' wool. ' ' Young leaves of the Horsechestnut are very thickly covered 

 with such a coat, of which only the slightest traces are to be seen 

 in the fully-grown leaf. The young leaves of the Beech are folded 

 like a fan for some time after they have left the enclosure of the 

 bud, and the folding is such that the only parts exposed are the 

 margins, the midrib, and the strongly-marked parallel veins. But 

 since all these parts are provided with hairs, the young leaf, as 



